Electric switch device



March 15, 1938. F, FAiLE 2,111,421

' ELECTRIC SWITCH DEVICE March 15, 1938. F. G. FAILE ELECTRIC SWITCH DEVICE Filed April 19, 1954 3 Shees-Shee't 2 gmc/Maw MJ' @ZM March 15, 1938. F, G, FAILE 2,.1'1,421

ELECTRIC SWITCH DEVICE Filed April 19, 1934 3 Sheets-Sheet 5 Patented Mar. 15, 1938 UNITED STATES PATENT FFE Fred G. Fails, Cleveland, Ohio, assigner to The Leonard Electric Manufacturing Company,

leveland, Ghic, a corporation of Ohio Application April i9, 1934,

6 Claims.

The general object of this invention is to provide an improved electric switch of the doublebreak multiple-contact type.

A further object is to provide a heavy duty multiple Contact electric switch wherein arcing during making and breaking of the circuits is greatly reduced and dangerous arcing eliminated.

A further object is to provide an electric switch the contacts of which must be closed by application of positive manual pressure and rigidly locked in closed position by the saine pressure as against being maintained in closed position by resilient or other non-positive means.

A specific object is to provide an improved manually operable electric switch wherein the operations of both opening and closing the cirn cuit or circuits are quickly accomplished manually but independently of the intentional speed of manual operation; in other words, a foolproof switch of this type.

A further object is to provide a quicknnake and quick break switch in which the separable circuit making and breaking elements are forcibly engaged and disengaged without depending upon springs to effect either engagement or disengagement or to maintain engagement.

Still another object is to provide an exceedingly compact industrial multiple contact doublebreak switch.

A further object is to provide an electric switch wherein the separable contact elements are positively engaged and disengaged by the application of manual pressure and with a wiping wedging action.

A further object is to provide a multiple contact switch and casing wherein the necessary operating elements extend only from the race of the casing, whereby a plurality of switches ci the type described may be mounted directly ad- 40 jacent each other and efec-tively yet independently operated.

A further object is to provide an industrial multiple contact switch and fuse supporting unit wherein fuses of different capacity and size may be easily and quickly installed by simple adjustment of the parts of the unit.

Still another object is to provide a multiple contact switch including spaced stationary contacts and bridging movable contacts cooperable therewith wherein the movable contacts are so arranged and supported that full electrical contact with the stationary contacts is assured notwithstanding variations in the contac ing surfaces and other variations incident to manufacturing the parts on a quantity production basis.

Serial No.

(Cl, E60-6G) A still further object is to provide a multiple Contact switch wherein the electrically independent conductor elements of the switch are more eiectively insulated from each other to reduce cross or short circuiting and leakage.

Other objects and features will become apparent from the following description wherein reference is made to the drawings. ille essential novel characteristics are summarized in the claims.

Referring to the drawings:

Fig, i is a plan view of the switch and casing, the right hand portion ci the casing being broken away to show the construction of certain of the switch parts and fuse supports;

Fig. Z is a sectional view as indicated by the line 2 2 on Fig. 1;

Fig. 3 is a side elevation of the mechanism which will be hereinafter referred to as the switch unit;

Fig. Il is a transverse sectional view of the switch unit taken along the line fl-l oi Fig. l;

Fig. 5 is a detail view showing seine el" the parts illustrated in 3 but in a different relative position; and

Figs. 6 and 7 are diagrammatic sectional views showing Various relationships between the stationaryand movable contact elements oi the switch; and

Fig. S is a detail view showing a modined arrangement of contacts.

Referring further 'to the drawings, the casing l :nay comprise a boxlike casing element having a bottorn^` panel il and perimetral walls 3 bent up from the base and suitably joined at the corners, the casing being completed by a hired cover panel and a movable. cover panel f5, both panels having perimetral side end wall flanges 'i adapted to telesoopingly engage the walls 3 oi the main part. rlhe panel is hinged to the panel 5 as at permitting the panel to be swung outwardly and away from the walls 3 exposing the interior or the. casing.

Located within the casing and secured to the base panel 2 is a block it of suitable insulation material such as colo molded asbestos composition, this bloclr being secured to the panel 2 as by four screws ii extending through openings in the cover portions oi the block and into threaded bosses i2 in 'the bottom panel. The block it constitutes a unitary rigid base for the switch unit. As shown in Figs. l, 2 and e, the block is rectangular in shape and carries at its sides relatively heavy bracket elements i3, preferably sheet rnetal, these being substantially identical in form. The bracket elements I3 have inwardly extending flanges i5 disposed between the underside of the switch base Ill and the casing panel 2, the bracket elements being secured to the base block I by means of the flanges and suitable screws (not shown) extending through the iianges and into suitable threaded inserts (not shown) in the base block.

The outer ends of the bracket elements I3 carry ears i bent parallel to the flanges I5, the ears being apertured to receive suitable fastening screws, one being shown at I'I, Figs. 1 and for securing the fixed panel 5 of the casing cover to the switch unit.

The separable contacts of the switch are arranged as follows:

Mounted on the base block I0 are a plurality of stationary electrical contacts 20, (six being present in the illustrated embodiment) these being substantially identical in form and electrically connected to electric service wires in a manner to be hereinafter described. The contacts 20 are arranged in pairs, see Fig. 2, and the contacts of each pair are adapted to be bridged by respective generally V-shaped movable contact elements or blades 22, three being shown (see Fig. 4) carried on a cross head 24 including an insulating cross bar 23 (asbestos composition e. g.) and a metal bar 25 inset into a rectangular channel 2I the outer side of the insulating bar. The bar 25 will be hereinafter referred to as the pressure bar and, being rectangular in cross section and about three times as deep as it is wide, the bar prevents any bending of the cross head such as would tend to make say one of the blades 22 seat or unseat with respect to its contacts 20 ahead of the other blades.

The bar 25 is less wide than the channel 21 wherefore the insulating bar 23 may float slightly with reference to the pressure bar which latter 1ras its ends slidably fitted to parallel slots 26 in ie respective brackets I3, the slots guiding the pressure bar for true right line movement in and out to open and close the switch contact elements 2D and 22. The pressure bar is secured in the channel 2l by cross pieces 28 (see Figs. 2 and 4) which are, in turn, securely fastened to the insulating bar 23 as by means of screws and threaded inserts (not shown) in the insulation material.

e individual sets of movable and stationary contacts and the conductor elements associated with the fixed contacts are effectively separated from each other by barrier strips 39 (hard asbestos board e. g.) and the outermost contacts and conductors, that is, those nearest the bracket elements I3 are insulated from the latter by barrier strips 3l, constructed similarly to the barrier strips 30. The contours of the barrier strips 3D and 3l are best illustrated in Fig. 2. The strips have substantially straight inner edges and these rest in grooves 33 in the base block I0, said edges extending the entire length of the base block. The barrier strips, incidentally, greatly strengthen the block against transverse cracking. Each of the strips 33 and 3l is cut cut at 34 substantially centrally thereof and rectangularly as shown in Fig. 2 to embrace the insulating cross bar 23. The latter has parallel grooves 35 on its opposite surfaces into which the marginal portions of the barrier strips adjacent the rectangular notches 34 extend.

The tongue and groove relationships just described between the insulating cross bar and the rectangular notches 34 in the barrier strips 3i) and 3| further insures the electrical independence of the stationary and movable contacts and conductors of the different sets notwithstanding a considerable accumulation of foreign matter which may be more or less electrically conductive. Likelihood of short or cross circuiting is further rendered negligible by reason of the fact that the overlapping surfaces of the insulation members clean themselves during the operation of the switch to open and closed position, that is during inward and outward throw of the cross head. The arrangement further permits the electrically independent contacts and conductors to be placed closer together, saving space, i. e. permitting greater compactness of construction. Further protection against the accumulation of foreign matter is afforded by cross strips of insulating material 35 and 38 (asbestos board e. g.), see Figs. 1 and 2. These strips are secured to the outer edge surfaces of the barrier strips 30 and 3i as by suitable screws 39 and hold the barrier strips firmly in parallel relationship.

It will be noted in Figs. 2 and 4 that the movable contacts 22 are secured in respective rectangular recesses or troughs 40 on the inward side of the insulating cross bar 23. It will also be noted from Fig. 4 particularly, that the same side of the insulating cross bar is recessed as at 4I for the reception of the barrier strips of insulation 30 and 3|. Thus when the insulating cross bar 23 is forced inwardly toward the base block I0, the different sets of contacts and conductors are further insulated from each other against cross circuiting by leakage by overlapping portions of the cross bar and the barrier strips. Likewise, the outermost contacts and conductors are fully insulated from the metal parts of the switch, particularly the brackets I3 and switch operating parts carried thereon.

The movable contacts or blades 22 (as shown in Figs. 6 and '7) each comprises a single V- shaped bar having outwardly extending ears 22. seated at the bottom of the respective rectangular troughs 40. Suitable screws 42, extending inwardly through openings 43 in the insulating bar 23, are threaded into the ears 22 and hold the contact members 22 in fixed position on the insulating bar 23. The stationary contacts 20 re also V-shaped and each comprises spaced contact arms 50, see Figs. 4, 6, and '7, connected by a base loop 5I. The base loop is generally rectangular as shown and the bottommost portion is apertured as at 52 to receive attaching screws 53 extending upwardly from the base block in suitable openings therein as shown in Fig. 2. Preferably the arms 50 are buttressed by generally U-shaped spring members 55, the arms of which extend in embracing relation to the contact arms 50. The bases of the spring members are likewise apertured to receive the screws 53. The screws threadingly engage openings 56 in conductor bars 51 and 51.

Referring to Fig. 6, it will be noted that the angularity between the arms of the V-shaped movable contacts or blades 20 and the resilient arms 50 of the xed contacts is dissimilar, the angle between the arms 5i) being smaller. The purpose of this is to provide a yielding wedging and sliding Contact between the arm portions of the contacts 20 and 22 as the same are brought together. Fig. 6 illustrates in broken lines at 22x the condition when the contacts 20 are first brought into engagement with the arms 59 and in Fig. 7, the full Contact position with respect to both cont-acts is shown.

As shown in Fig. 2, the conductor bars 5l (one being shown) extend to suitable detachable conductor wires 58 secured as by screws 59 to threaded metallic inserts 59' in the base block. The bars 51 extend from the respective oontacts 20 and are electrically associated with suitable iuse clips 60, see Figs. 1 and 2. The fuse clips 60 are of conventional construction and may be secured to the base block I0 by suitable screws Si engaging threaded inserts 6l in the base block.

A fuse of conventional type adapted to be supported by clips such as 60 is shown in Fig. 1 at F. Each of the fuses has one of its ends supported by one of the clips 60, just described, and the opposite end by one of a series of similar fuse clips 62 (one being shown) connected with conductor wires 63. The clips 62 and connections are carried on a common insulating block t5 secured to the base panel 2 of the switch casing as by suitable screws 61. The block may be positioned as illustrated in Fig. 1 or, if it is desired that a shorter fuse (of less capacity) be employed, then. the b-lock 65 may be moved toward the base block l of the switch, the screws 61 then entering other openings, one of which is shown at 68, Fig. 1, in the casing panel 2. This adjustment may be done by means of a screw driver without having to remove the casing l from. the wall or to disturb the switch unit.

The operating mechanism for the cross head 24 is best shown in Figs. 1, 3 and 5. Supported on a suitable rock shaft 10 mounted in the brackets i3 are a pair of pressure bar operating cams 12 and 13. One of these operating cams, namely 13, has an extension 14 passing outwardly through a slot 5a in the fixed portion 5 of the casing cover and this extension 14 carries an operating handle 15, mounted on a suitable pin 16, by which the operating cams are turned manually to move the cross head. The extension 14 also has an arm 14a (Fig. 3) projecting into closely overlying relation to the movable cover panel 6 when the switch is closed whereby opening of this cover panel about its hinges 8 automatically opens the switch contacts. Openings 14h and 14o' may also be provided in the cam extension 14 for the purpose of permitting the cam to be locked (as with a padlock) with the switch contacts in open or closed position as desired.

Preferably the pressure bar operating cams have non-circular openings 11, one only being shown, embracing complementary non-circular f end portions of the rock shaft 10 and the cam may be held onto said non-circular shaft portions by suitable cotter pins as shown. The opposite ends of the pressure bar 25 have substantially cylindrical pins 18 preferably integral therewith and extending through cam slots. 19 in the respective cams 12 and 13. The slots are identical in contour and the contour is best illustrated in Fig. 5. The pressure bar pins 18 carry suitable hardened rollers 80 which ride on the cam surfaces of the slots 19 which will now be described.

Each cam slot 19 has a portion 19a extending generally radially from the axis of the rock shaft and a circumferentially extending portion 19h, the latter portions forming retaining shoulders 19e for the respective rollers 8B. When the switch contacts 2B are in the open position, illustraied in Figs. 2 and 4, the rollers 80 occupy the radial portions 19a of the cam slots and when lthe contacts are closed, see Figs. 3 and '7, the

rollers occupy the circumferentially extending portions 19h of the cam slots and are retained in this position, see Fig. 3, by the shoulder 19e. lThe path of the shoulder 19e intercepts a` poru tion of the normal path of the roller while the roller is traveling along such portion and consequently the roller must be slightly stressed out of its normal path by the shoulder to pass the same, whereupon it lies in the portion 1Gb as shown in Fig. 5 and must remain in this position due to the fact that the circumference of the roller is closer, at a point beyond the shoulder, to the pivotal axis 10 than is the point of contact of the shoulder with the roller circumference. This accomplishes the desired result of holding the blades and contacts 22 and 2S rmly in full contact against accidental dislodgment and assists in the quick making and breaking operations oi the switch by interposing a hazard with respect to both operations. Various parts of the switch are subject to substantial stresses as the rollers ride from one portion of the cam slots to the other but the parts so subjected are sturdily built to withstand the strains and the rollers and cams are hardened to withstand the wear.

The cross head 24 is normally biased into open position by suitable springs 82 and levers 83, the springs being connected to the respective bracket elements i3 and to the levers 83, as shown in Fig. 3. The levers are pivoted to suitable xed pins 34 on the brackets i3 and have slots 85 emb-racing the pins 18 of the pressure bar. As will be seen from Fig. 3, the springs 82 tend, on contracting, to throw the pressure bar to switch contact releasing position. These springs and levers 82 and 83 accomplish quick breaking of the contacts at 2? and 22 as soon as the pressure bar operating cams are turned to move the rollers 8G beyond the shoulders 19o. The manual force necessarily required to release the rollers adds to the quick breaking action or the springs 82.

In order that the operator cannot hold back the cross head against the quick breaking action, just described, the operating handle has a lost motion connection with the cam 13, as illustrated in Fig. 3.

To secure quick making of the contacts a sliding bar 90 is provided generally parallel t the slots 26 of the bracket element i3 shown i Fig. 4, the bar 9U being carried on the pin 1 between the cam 13 and lever 83. A strap 9 is shown for additionally securing the bar Sii in position, the strap being secured to the adjacent bracket I3 as by a rivet 94 and screw 94 the latter permitting the strap to be swung aside about the rivet to permit assembly of the bar 90 into position. Near the lower end of the bar 9U is an inwardly extending pin 9i of a diameter substantially the same as the width of the slot 26 but easily slidable therein. The slot 25 has, near its lower end, a notch G2 which, in the closing operation of the switch, receives the pin 9| as a hazard and impedes the closing operation of the switch due to the fact that the end of the bar 9D, which carries the pin 9|, is drawn toward the notch by a suitable tension spring 93 connected at its opposite ends to the bracket and bar 90 respectively.

The relationship of the switch contacts and blades at a time when the pin l engages the notch 92 is shown in Fig. 6, (full line showings of both parts). Referring to Fig. 5 and assurn ing that the cam 13 is being rotated in a counterclockwise direction (closing the switch) it will be seen that before the rollers B0 can enter the circumferentially extending portions '19h of the cam slots the pin 9| will have to be forced out of the notch. This requires considerable force and the speed and pressure of the operators hand on the handle 'l5 must be increased several fold after the pin encounters the notch 92 and before the switch contacts can be fully closed. The detaining forces are released upon the pin slipping out of the notch but the excess pressure on the operating handle continues momentarily and is always sufficient to quickly close the contacts and seat the rollers into the circumferential portions of the cam slots, mechanically locking the contacts in closed position (see Figs. 3 and 7).

In connection with Fig. 5 it should be noted that the pin 9| is embraced by the notch 92 about substantially one half of the pin circumference. In addition, a line through the axis of the pin 9| and axis of the pin 10, by which the bar 9G is carried, intersects the wall of the notch 92 beyond the pin in the direction of movement toward contact making position. Thus when moved toward contact making position, as` the pin 9| becomes fully seated in the notch 92, it becomes very diicult to unseat by pressure exerted on the bar in the same direction. Upon movement in the opposite direction, however, this line of force lies outwardly beyond the wall of the notch so that the pin can wedge the bar 90 to the right and release. It is for this reason that the speed of movement, as above mentioned, is important. When operating at suflicient speed the pin 9| will not become fully seated in the notch as it passes the same and consequently the resisting wall of the notch will be operating well out on the sloping surface of the pin 9| and the bar 90 will be moved onward to the right. A speed sufficient to cause the pin 9| to partially jump the notch 92, however, is also such as to assure that the contact making position will be reached as the operator cannot even intentionally arrest movement from so lgreat a speed between the time the pin 9| jumps the notch and the blades come into contact. When the pin 9| has moved to a position in which it has passed the notch 92 or is only partially seated therein so that it can be moved onwardly and not restrained by the notch, the roller 80 will have passed the peak 'l9c of the cam and will promptly be locked in position for maintaining the contact relation of the contactors.

In heavier duty types of switches it is necessary to increase the gauge of the metal of the contacts to an extent such that the design of contacts illustrated in Figs. 4 and l is somewhat impractical. In such cases, it is preferred to make the generally V-shaped movable contact members or blades in generally triangular shape, as illustrated in Fig. 8 at |90, the edges of the strip forming the blade being adjacent the arms |0| of the fixed contacts rather than opposite the fixed contacts as in the previously described arrangement. This modification of contacts preferably includes pressure affording spring elements such as |02 for the movable contact. The spring |92, as illustrated, comprises a generally U-shaped strip of spring metal secured between the arms |03 of the movable Contact, with the base secured to the closed portion of the strip forming the blade |00 `as by a rivet or screw (not shown). The movable contact may also be provided with one or more reinforcing bars of copper e. g. as at |05 and |06, the portion thereof between the two wedge-shaped elements of a single contact bar being secured to the insulating cross bar 23 as by screws for example (not shown) entering suitable openings in the reinforcing bar or bars. The stationary contacts may be made as shown in Fig. 8, separate arm strips being shown as secured in slots |01 in .a base element oi' copper e. g. |08.

The arrangement of V-shaped contact elements may be reversed if desired; that is to say, the wedge members may be carried on the base block in some instances and the wedge receiving contact members carried on the cross head.

I claim:

1. In an electric switch, an insulating base, spaced contacts carried by the base, a. frame carried by the base and surmounting the same, said frame having parallel slots at opposite sides of the base, a cross head mounted in said slots and a bridging contact element carried on the cross head adapted to cooperate with the spaced contacts, operating means carried on said frame for moving the cross head inwardly and outwardly in the slots, and a hazard device carried by said cross head and comprising a bar pivotally mounted on the crosshead for swinging movement transversely of one of the slots and having a pin slidable in said one of the slots, the latter slot having a notch adapted to receive the pin during its inward movement in a direction to close the switch, and resilient means yieldably urging the bar transversely of said one of said slots and opposing movement of the pin out of the notch at a time when the electrical contacts are in approximately closed position.

2. In an electric switch, cooperable contactors, a carrier supporting one of said contactors and movable toward and away from the other contactor for effecting the contact relation, a frame movably supporting said carrier, lineal guides for guiding said contactors to and from contact relation, an operating cam pivotally mount ed on the frame, a pin on the carrier engageable with the cam for operation of the carrier thereby and guided lineally in said guides, and the pivotal axis of the cam being spaced laterally from the path of travel of the pin, said cam including a pin actuating cam surface extending generally radially from the pivot axis of the cam and shaped so that the force of `the cam is applied generally parallel to the lineal guides during substantially the entire movement of the carrier and a pin retaining surface extending generally circumferentially of the pivot axis of the cam, said circumferentially extending surface being engageable with the pin only in the closed position of the contactors and having a shoulder for locking the pin in seated position, means yieldably urging said carrier away from contact making position, hazard means cooperable with the carrier when the carrier is moved almost to contact making position by the cam with a predetermined force applied to the cam and opposing further movement toward said position, said hazard means being inoperative to oppose said movement consequent upon a pre- -determined greater force .applied to .and by said cam for moving the carrier toward the contact position, said hazard means being positioned to operate just prior to the engagement of the pin by the pin retaining surface of the cam.

3. In an electrical switch, a pair of cooperable contactors, a carrier supporting one contactor and being movable toward and away from the other contactor for effecting the contact relation, a frame, a guideway in the frame, a guide on the carrier accommodated in the guideway for guiding the carrier in a generally linear path to and from contact making position, a cam pivotally mounted on the frame for rocking movement, the pivotal axis being offset transversely of the path of travel of the carrier from the guideway, said cam having an operating surface coacting with the guide for moving the carrier to Contact making position, said surface extending transversely of the path of travel of the guide in the guideway and being congured to extend at substantially right angles to the guideway at the instantaneous guide engaging portion of the surface throughout the major portion of the travel of the carrier, whereby the force and movement delivered by the surface is substantially directly parallel to and along the guideway.

l. In an electrical switch, a pair of cooperable contactors, a carrier supporting one contactor and being movable toward and away from the other contactor for eiecting the contact relation, a frame, a guideway in the frame, a guide on the carrier accommodated in the guideway for guiding the carrier in a generally linear path to and from contact making position, a camA pivotally mounted on the frame for rocking movement, the pivotal axis being offset transversely of the path of travel of the carrier from the guideway, and positioned close to the level of the guide when the carrier is in fully open position, said cam having an operating surface coacting with the guide for moving the carrier to contact making position, said surface extending transversely of the path of travel of the guide in the guideway and being configured to extend at substantially right angles to the guideway at the instantaneous guide engaging portion of the surface throughout the major portion of the travel of the carrier, whereby the force and movement delivered by the surface is substantially directly parallel to and along the gudeway.

5. In an electrical switch, a pair of cooperable contactors, a carrier supporting one contactor and being movable toward and away from the other contactor for effecting the Contact relation, a frame, a guideway in the frame, a guide on the carrier accommodated in the guideway for guiding the carrier in a generally linear path to and from contact making position, a cam pivotally mounted on the frame for rocking movement, the pivetal axis being offset transversely of the path of travel of the carrier from the gudeway, said cam ving an operating surface coasting with the ne for moving the carrier to contact making osition, said surface extending transversely of path of travel of the guide in the guideway nd being configured to extend at an angle to the guideway at the instantaneous guide engaging portion of the surface such that the greatest component of force of the surface on the guide is parallel to the guideway throughout substantially the entire movement of the carrier.

6. In an electrical switch, a switch box, a pair of cooperable contactors mounted therein, a carrier supporting one contactor and being movable toward and away from the other contactor for effecting the contact relation, a frame for supporting and guiding the movable contactor, a cam pivotallv mounted on the frame for rocking movement and being cooperable with the movable contactor for moving the same to contact making position, said switch box having a front wall extending at right angles to the plane of the cam and a door hinged to the switch box and forming a continuation of the front Wall when closed, said front wall having a slot, said cam having a portion extending through said slot to the outside ci the box, said extending portion of the cam having a lug portion overlying said door when the door is in closed position and being engaged by said door upon opening thereof to move the cam to contact breaking position, and an operating handle connected to the outwardly extending portion of the cam.

FRED G. FAILE. 

